Heritability of some yield components and kernel quality in sweet corn --Has, V Ten sugary1 inbred lines developed at the Agricultural Research Station of Turda were chosen for this study (Table 1). They were crossed using the factorial (m n + n m) mating design with reciprocal combinations in order to estimate GCA and SCA for inheritance of some ear and kernel characteristics and kernel chemical composition (Table 2, 3, 4), genetic value of parental inbreds, and phenotypic and genotypic correlations among traits. Genotype x year interactions influenced the expression of the most traits, emphasizing the importance of their evaluation in different years. The highly significant GCA mean squares for yield components points to the importance of additive gene action in the genotypes studied here. The significant SCA effects for all traits point to nonadditive gene action as well, although on the basis of comparative mean squares, additive gene action appears the more important. SCA variance was larger than GCA variance only for kernel chemical compositions and pericarp thickness. The predominance of SCA effects indicates that the pattern of carbohydrate accumulation in a hybrid depended upon the specific interaction of inbred lines involved in the crosses. Reciprocal hybrid differences were detected for all kernel compositions analyzed. These differences should be attributed to an interaction of cytoplasm x nuclear genome. Our sugary parental lines TA 28, TA 22, TA 25 transmitted a large number of positive traits in their crosses. An unfavorable genetic correlation between sucrose - row number, total sugar - ear weight suggest that in breeding programs it�s difficult enough to obtain high yield sweet corn hybrids with good quality.

Table 1. Pedigree and genealogy of the sweet inbred lines.
 
Nr. crt. Inbred Pedigree / Origin Genealogy
1. SW 87 SUA -
2. TA 22 su Q 206 - Canada 3603-1-1-7-
3. TA 27 su Reward - SUA 5103-6-3-5
4. TA 28 su Golden Beauty - SUA 7188-1-1-3-
5. TD 103 su How Sweet It Is - SUA 7208-1-1-1-
6. TA 25 su Reward - SUA  3610-2-4-1-
7. TA 26 su Reward - SUA 5093-1-1-1-
8. TD 101 su Aux 5651 - SUA 3607-2-1-3-
9. TD 282 su Silver Queen - SUA 3870-10-2-1-
10. TD 102 su Aromatnaja - R.Moldova 7208-3-1-1-

Table 2. Genetic variances (s2) involved in the expression of ear and kernel characteristics.
 
   
Weight
Ear
Row 
Ear
Kernel
Eating
Source of variation
DF
ear
husk
length
number
shape
depth
quality
TOTAL
547
              
YEARS (Y)
1
38250.83**
12229.06**
8.61*
2.36**
8.61**
13.86*
12.66**
REPLICATION
2
262.84
306.42
0.80
0.35
1.02
5.49
5.97
ERROR (a)
2
79.91
220.25
0.43
0.36
1.12
3.81
0.17
GENOTYPES (G)
15
2490.48**
1029.45**
10.09**
17.98**
5.15**
5.76**
2.30**
-Additive actions (Am)
(3)
9672.33**
3114.74**
31.63**
58.47**
16.57**
10.99
3.45
-Additive actions (An)
(1)
6112.29**
3075.17**
41.67**
77.19**
20.53**
19.74**
4.08
-Non-additive actions (NA)
(3)
1854.22**
848.10**
1.35**
3.95**
1.42**
5.08**
2.27**
-Differences m/n
(1)
322.89
111.26
3.05*
2.62
0.38
4.33*
4.13**
-Maternal effects (Mm)
(3)
171.67
268.21**
1.06
1.62
1.13
1.28
2.21
- Maternal effects (Mn)
(1)
541.54**
289.81**
3.75
0.77
0.76
2.04
0.97
Reciprocal effects (R)
(3)
157.55
59.08
1.09**
1.56**
0.54
1.27*
1.05**
GENOTYPES x YEAR (G x Y)
15
1480.66**
333.71**
2.32**
3.26**
0.82**
6.52**
1.75**
- Am x Y
(3)
4611.29**
859.99*
8.20**
8.49**
1.79
17.32
3.08
- An x Y
(1)
3933.88*
485.81
4.71**
8.40**
1.13
9.33
2.55
NA x Y
(3)
1522.78**
339.50**
1.01**
1.37**
0.96**
7.57**
1.02**
- m/n x Y
(1)
239.63
213.12
0.41
1.21
1.24**
4.10
1.20**
- Mm x Y
(3)
84.69
95.95
0.68
2.37
0.52
3.12
1.96
- Mn x Y
(1)
307.73
222.88
0.64
2.07
0.20
3.13
2.29
- R x Y
(3)
154.58
178.74
1.42
1.28**
0.38
2.29**
1.08**
ERROR (b)
60
91.23
133.70
0.36
0.34
0.51
0.80
0.21

Table 3. Genetic variances (s2) involved in the expression of some kernel and ear characteristics of sweet corn .
 
             
   

Pericarp

Pericarp

  

Husk

Flag leaves
Plant sensitivity to 
Biotest for kernel sensitivity to
Source of variation DF thickness Weight Tip fill length length Aphis sp. F.moniliforme
TOTAL 47              
REPLICATION 2 172.40 0.37 0.04 0.07 2.08 114.38 54.87
GENOTYPES 15 3325.52** 6.37** 2.31** 20.61** 34.14** 752.81** 125.03**
-additive actions (Am) (3) 3122.74 4.70 0.85 6.72** 28.22 1687.72 295.34*
-additive actions (An) (1) 1354.69 2.43 25.23** 248.21** 376.88** 210.13 463.64*
-non-additive actions (NA) (3) 2404.69** 18.39** 0.57 0.40 7.57 1661.97** 30.58
-differences m/n (1) 5742.19** 0.80* 1.84* 1.02* 0.46 512.00* 11.19
-maternal effects (Mm) (3) 4156.08 3.45 0.55 0.41 2.27 150.30* 26.44
-maternal effects (Mn) (1) 379.69 5.07 0.48 0.48 2.66 50.00 23.13
-reciprocal effects (R) (3) 4451.91** 2.54** 0.40 0.28 5.98 6.69 106.80
Error  30 79.06 0.19 0.31 0.21 3.45 106.19 44.80

Table 4. Genetic variances (s2) involved in the expression of kernel quality of sweet corn .
 
   
Kernel contents in:
    dry total          
Source of variation DF matter sugar sucrose phytoglycogen starch protein fats
TOTAL 179              
REPLICATION 5 1.66 0.10 0.001 0.001 0.25 0.01 0.01
GENOTYPES 87 14.56** 30.31** 2.27** 7.77** 45.56** 2.27** 0.67**
-additive actions (Am) (11) 25.20 79.65 4.31 7.36 70.94 5.36* 1.47
-additive actions (An) (10) 25.25 38.74 3.28 22.62 66.11 1.09 0.48
-non-additive actions (NA) (20) 12.92** 39.31** 3.27** 6.15** 45.21** 2.09** 0.74**
-differences m/n (5) 11.86** 9.85** 1.16** 3.04** 6.27** 1.37** 0.29**
-maternal effects (Mm) (11) 11.97 12.72 0.98 2.76 27.98 1.55 0.41
-maternal effects (Mn) (10) 6.47 5.96 0.83 5.44 26.29 1.54 0.75
-reciprocal effects (R) (20) 11.13** 16.94** 1.34** 7.29** 50.83** 2.32** 0.44**
Error  87 0.27 0.09 0.001 0.001 0.35 0.001 0.01

 
 
 
 
 
 
 

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